1
|
Abrosimov R, Baeken MW, Hauf S, Wittig I, Hajieva P, Perrone CE, Moosmann B. Mitochondrial complex I inhibition triggers NAD +-independent glucose oxidation via successive NADPH formation, "futile" fatty acid cycling, and FADH 2 oxidation. GeroScience 2024; 46:3635-3658. [PMID: 38267672 PMCID: PMC11226580 DOI: 10.1007/s11357-023-01059-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 12/27/2023] [Indexed: 01/26/2024] Open
Abstract
Inhibition of mitochondrial complex I (NADH dehydrogenase) is the primary mechanism of the antidiabetic drug metformin and various unrelated natural toxins. Complex I inhibition can also be induced by antidiabetic PPAR agonists, and it is elicited by methionine restriction, a nutritional intervention causing resistance to diabetes and obesity. Still, a comprehensible explanation to why complex I inhibition exerts antidiabetic properties and engenders metabolic inefficiency is missing. To evaluate this issue, we have systematically reanalyzed published transcriptomic datasets from MPP-treated neurons, metformin-treated hepatocytes, and methionine-restricted rats. We found that pathways leading to NADPH formation were widely induced, together with anabolic fatty acid biosynthesis, the latter appearing highly paradoxical in a state of mitochondrial impairment. However, concomitant induction of catabolic fatty acid oxidation indicated that complex I inhibition created a "futile" cycle of fatty acid synthesis and degradation, which was anatomically distributed between adipose tissue and liver in vivo. Cofactor balance analysis unveiled that such cycling would indeed be energetically futile (-3 ATP per acetyl-CoA), though it would not be redox-futile, as it would convert NADPH into respirable FADH2 without any net production of NADH. We conclude that inhibition of NADH dehydrogenase leads to a metabolic shift from glycolysis and the citric acid cycle (both generating NADH) towards the pentose phosphate pathway, whose product NADPH is translated 1:1 into FADH2 by fatty acid cycling. The diabetes-resistant phenotype following hepatic and intestinal complex I inhibition is attributed to FGF21- and GDF15-dependent fat hunger signaling, which remodels adipose tissue into a glucose-metabolizing organ.
Collapse
Affiliation(s)
- Roman Abrosimov
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Marius W Baeken
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Samuel Hauf
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Ilka Wittig
- Institute for Cardiovascular Physiology, Goethe University, Frankfurt, Germany
| | - Parvana Hajieva
- Institute for Translational Medicine, MSH Medical School, Hamburg, Germany
| | - Carmen E Perrone
- Orentreich Foundation for the Advancement of Science, Cold Spring-On-Hudson, NY, USA
| | - Bernd Moosmann
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
| |
Collapse
|
2
|
Göransson O, Kopietz F, Rider MH. Metabolic control by AMPK in white adipose tissue. Trends Endocrinol Metab 2023; 34:704-717. [PMID: 37673765 DOI: 10.1016/j.tem.2023.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 09/08/2023]
Abstract
White adipose tissue (WAT) plays an important role in the integration of whole-body metabolism by storing fat and mobilizing triacylglycerol when needed. The released free fatty acids can then be oxidized by other tissues to provide ATP. AMP-activated protein kinase (AMPK) is a key regulator of metabolic pathways, and can be targeted by a new generation of direct, small-molecule activators. AMPK activation in WAT inhibits insulin-stimulated lipogenesis and in some situations also inhibits insulin-stimulated glucose uptake, but AMPK-induced inhibition of β-adrenergic agonist-stimulated lipolysis might need to be re-evaluated in vivo. The lack of dramatic effects of AMPK activation on basal metabolism in WAT could be advantageous when treating type 2 diabetes with pharmacological pan-AMPK activators.
Collapse
Affiliation(s)
- Olga Göransson
- Lund University, Department of Experimental Medical Science, BMC, 221 84 Lund, Sweden.
| | - Franziska Kopietz
- Lund University, Department of Experimental Medical Science, BMC, 221 84 Lund, Sweden
| | - Mark H Rider
- Université catholique de Louvain (UCLouvain) and de Duve Institute, Avenue Hippocrate 75, 1200 Brussels, Belgium
| |
Collapse
|
3
|
Ji H, Englmaier F, Morigny P, Giroud M, Gräsle P, Brings S, Szendrödi J, Berriel Diaz M, Plettenburg O, Herzig S, Rohm M. Development of a peptide drug restoring AMPK and adipose tissue functionality in cancer cachexia. Mol Ther 2023; 31:2408-2421. [PMID: 37408309 PMCID: PMC10422018 DOI: 10.1016/j.ymthe.2023.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/01/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023] Open
Abstract
Cancer cachexia is a severe systemic wasting disease that negatively affects quality of life and survival in patients with cancer. To date, treating cancer cachexia is still a major unmet clinical need. We recently discovered the destabilization of the AMP-activated protein kinase (AMPK) complex in adipose tissue as a key event in cachexia-related adipose tissue dysfunction and developed an adeno-associated virus (AAV)-based approach to prevent AMPK degradation and prolong cachexia-free survival. Here, we show the development and optimization of a prototypic peptide, Pen-X-ACIP, where the AMPK-stabilizing peptide ACIP is fused to the cell-penetrating peptide moiety penetratin via a propargylic glycine linker to enable late-stage functionalization using click chemistry. Pen-X-ACIP was efficiently taken up by adipocytes, inhibited lipolysis, and restored AMPK signaling. Tissue uptake assays showed a favorable uptake profile into adipose tissue upon intraperitoneal injection. Systemic delivery of Pen-X-ACIP into tumor-bearing animals prevented the progression of cancer cachexia without affecting tumor growth and preserved body weight and adipose tissue mass with no discernable side effects in other peripheral organs, thereby achieving proof of concept. As Pen-X-ACIP also exerted its anti-lipolytic activity in human adipocytes, it now provides a promising platform for further (pre)clinical development toward a novel, first-in-class approach against cancer cachexia.
Collapse
Affiliation(s)
- Honglei Ji
- Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Felix Englmaier
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute of Medicinal Chemistry, Molecular Targets and Therapeutics Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Institute of Organic Chemistry, Center of Biomolecular Research, Leibniz University Hannover, 30167 Hannover, Germany
| | - Pauline Morigny
- Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Maude Giroud
- Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Pamina Gräsle
- Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Sebastian Brings
- Department of Internal Medicine I and Clinical Chemistry, Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; Department of Nuclear Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Julia Szendrödi
- Department of Internal Medicine I and Clinical Chemistry, Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Mauricio Berriel Diaz
- Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Oliver Plettenburg
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute of Medicinal Chemistry, Molecular Targets and Therapeutics Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Institute of Organic Chemistry, Center of Biomolecular Research, Leibniz University Hannover, 30167 Hannover, Germany; Laboratory of Nano- and Quantum Engineering (LNQE), Leibniz University Hannover, 30167 Hanover, Germany; Institute of Lung Health (ILH), 35392 Gießen, Germany.
| | - Stephan Herzig
- Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Chair Molecular Metabolic Control, Technical University Munich, 81675 Munich, Germany.
| | - Maria Rohm
- Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Center Munich, 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Unit, Heidelberg University Hospital, 69120 Heidelberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
| |
Collapse
|
4
|
Park J, Rah SY, An HS, Lee JY, Roh GS, Ryter SW, Park JW, Yang CH, Surh YJ, Kim UH, Chung HT, Joe Y. Metformin-induced TTP mediates communication between Kupffer cells and hepatocytes to alleviate hepatic steatosis by regulating lipophagy and necroptosis. Metabolism 2023; 141:155516. [PMID: 36773805 DOI: 10.1016/j.metabol.2023.155516] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/24/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023]
Abstract
OBJECTIVE Emerging evidence suggests that crosstalk between Kupffer cells (KCs) and hepatocytes protects against non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanisms that lead to the reduction of steatosis in NAFLD remain obscure. METHODS Ttp+/+ and Ttp-/- mice were fed with a high-fat diet. Hepatic steatosis was analyzed by Nile Red staining and measurement of inflammatory cytokines. Lipid accumulation and cell death were evaluated in co-culture systems with primary hepatocytes and KCs derived from either Ttp+/+ or Ttp-/- mice. RESULTS Tristetraprolin (TTP), an mRNA binding protein, was essential for the protective effects of metformin in NAFLD. Metformin activated TTP via the AMPK-Sirt1 pathway in hepatocytes and KCs. TTP inhibited TNF-α production in KCs, which in turn decreased hepatocyte necroptosis. Downregulation of Rheb expression by TTP promoted hepatocyte lipophagy via mTORC1 inhibition and increased nuclear translocation of transcription factor-EB (TFEB). Consistently, TTP-deficient NAFLD mice failed to respond to metformin with respect to alleviation of hepatic steatosis, protection of hepatocyte necroptosis, or induction of lipophagy. CONCLUSIONS TTP, which is essential for the protective effects of metformin, may represent a novel primary therapeutic target in NAFLD.
Collapse
Affiliation(s)
- Jeongmin Park
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Republic of Korea
| | - So-Young Rah
- National Creative Research Laboratory for Ca(2+) signaling Network, Chonbuk National University Medical School, Jeonju 54907, Republic of Korea
| | - Hyeong Seok An
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Jong Youl Lee
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Gu Seob Roh
- Department of Anatomy and Convergence Medical Science, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea
| | | | - Jeong Woo Park
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Chae Ha Yang
- College of Korean Medicine, Daegu Haany University, Daegu 42158, Republic of Korea
| | - Young-Joon Surh
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea; Cancer Research Institute, Seoul National University, Seoul 03080, Republic of Korea
| | - Uh-Hyun Kim
- Department of Biochemistry, School of Medicine, Wonkwang University, Iksan 54538, Republic of Korea
| | - Hun Taeg Chung
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Republic of Korea.
| | - Yeonsoo Joe
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Republic of Korea.
| |
Collapse
|
5
|
Wichai U, Keawsomnuk P, Thongin S, Mukthung C, Boonthip C, Pittayakhajonwut P, Ketsawatsomkron P, Bunyapraphatsara N, Muta K. Cellular responses to 8-methyl nonanoic acid, a degradation by-product of dihydrocapsaicin, in 3T3-L1 adipocytes. BMC Complement Med Ther 2023; 23:18. [PMID: 36681810 PMCID: PMC9862568 DOI: 10.1186/s12906-023-03844-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 01/12/2023] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Capsaicinoids, such as dihydrocapsaicin (DHC), exert the health-promoting effects of chili peppers on energy metabolism. The metabolic responses to capsaicinoids are primarily mediated through transient receptor potential cation channel subfamily V member 1 (TRPV1). However, the varying contributions of their metabolites to beneficial health outcomes remain unclear. 8-methyl nonanoic acid (8-MNA), a methyl-branched medium chain fatty acid (MCFA), is an in vivo degradation by-product of DHC. Since MCFAs have emerged as metabolic modulators in adipocytes, here we examined various cellular responses to 8-MNA in 3T3-L1 adipocytes. METHODS The viability of 3T3-L1 adipocytes exposed to various concentrations of 8-MNA was assessed by the Calcein AM assay. Biochemical assays for lipid accumulation, AMP-activated protein kinase (AMPK) activity, lipolysis and glucose uptake were performed in 3T3-L1 adipocytes treated with 8-MNA during 48-h nutrient starvation or 5-day maturation. RESULTS 8-MNA caused no impact on cell viability. During nutrient starvation, 8-MNA decreased lipid amounts in association with AMPK activation, a molecular event that suppresses lipogenic processes. Moreover, 3T3-L1 adipocytes that were treated with 8-MNA during 5-day maturation exhibited a reduced lipolytic response to isoproterenol and an increased glucose uptake when stimulated with insulin. CONCLUSIONS These results suggest that 8-MNA derived from DHC modulates energy metabolism in adipocytes and also support the idea that the metabolic benefits of chili consumption are partly attributable to 8-MNA.
Collapse
Affiliation(s)
- Uthai Wichai
- grid.412029.c0000 0000 9211 2704Department of Chemistry and Center of Excellence in Biomaterials, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Ploychanok Keawsomnuk
- grid.10223.320000 0004 1937 0490Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Bang Pla, Bang Phli, Samut Prakan, 10540 Thailand
| | - Saowarose Thongin
- grid.10223.320000 0004 1937 0490Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Bang Pla, Bang Phli, Samut Prakan, 10540 Thailand
| | - Chaiyot Mukthung
- grid.412029.c0000 0000 9211 2704Department of Chemistry, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Chatchai Boonthip
- grid.412029.c0000 0000 9211 2704Department of Chemistry, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Pattama Pittayakhajonwut
- grid.425537.20000 0001 2191 4408National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, Thailand
| | - Pimonrat Ketsawatsomkron
- grid.10223.320000 0004 1937 0490Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Bang Pla, Bang Phli, Samut Prakan, 10540 Thailand
| | - Nuntavan Bunyapraphatsara
- grid.10223.320000 0004 1937 0490Department of Pharmacognosy, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Kenjiro Muta
- grid.10223.320000 0004 1937 0490Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Bang Pla, Bang Phli, Samut Prakan, 10540 Thailand
| |
Collapse
|
6
|
Szkudelski T, Konieczna K, Szkudelska K. Regulatory Effects of Metformin, an Antidiabetic Biguanide Drug, on the Metabolism of Primary Rat Adipocytes. Molecules 2022; 27:molecules27165250. [PMID: 36014488 PMCID: PMC9415039 DOI: 10.3390/molecules27165250] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/12/2022] [Accepted: 08/13/2022] [Indexed: 11/16/2022] Open
Abstract
Metformin is a biguanide compound commonly applied in humans with type 2 diabetes. The drug affects different tissues, including fat tissue. The direct influence of metformin on cells of fat tissue, i.e., adipocytes, is poorly elucidated. In the present study, the short-term (4-h) effects of metformin on lipogenesis, glucose transport, lipolysis, and lactate release in primary rat adipocytes were explored. It was demonstrated that metformin reduced insulin-induced lipogenesis and increased glucose transport into adipocytes. The tested compound also decreased lactate release from fat cells. It was shown that metformin substantially limited lipolysis stimulated by epinephrine (adrenergic receptor agonist) and dibutyryl-cAMP (direct activator of protein kinase A). Moreover, metformin decreased the lipolytic process triggered by DPCPX (adenosine A1 receptor antagonist). In the case of each lipolytic stimulator, the drug evoked a similar inhibitory effect in the presence of 3 and 12 mM glucose. The lipolytic response of adipocytes to epinephrine was also found to be reduced by metformin when glucose was replaced by alanine. It was demonstrated that the tested compound limits the release of both glycerol and fatty acids from fat cells. The results of the present study provided evidence that metformin significantly affects the metabolism of primary rat adipocytes. Its action covers processes related to lipid accumulation and release and occurs after relatively short-term exposure.
Collapse
|
7
|
Boone-Villa D, Ventura-Sobrevilla J, Aguilera-Méndez A, Jiménez-Villarreal J. The effect of adenosine monophosphate-activated protein kinase on lipolysis in adipose tissue: an historical and comprehensive review. Arch Physiol Biochem 2022; 128:7-23. [PMID: 35143739 DOI: 10.1080/13813455.2019.1661495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
CONTEXT Lipolysis is one of the most important pathways for energy management, its control in the adipose tissue (AT) is a potential therapeutic target for metabolic diseases. Adenosine Mono Phosphate-activated Protein Kinase (AMPK) is a key regulatory enzyme in lipids metabolism and a potential target for diabetes and obesity treatment. OBJECTIVE The aim of this work is to analyse the existing information on the relationship of AMPK and lipolysis in the AT. METHODS A thorough search of bibliography was performed in the databases Scopus and Web of Knowledge using the terms lipolysis, adipose tissue, and AMPK, the unrelated publications were excluded, and the documents were analysed. RESULTS Sixty-three works were found and classified in 3 categories: inhibitory effects, stimulatory effect, and diverse relationships; remarkably, the newest researches support an upregulating relationship of AMPK over lipolysis. CONCLUSION The most probable reality is that the relationship AMPK-lipolysis depends on the experimental conditions.
Collapse
Affiliation(s)
- Daniel Boone-Villa
- School of Medicine Northern Unit, Universidad Autonoma de Coahuila, Piedras Negras, México
| | | | - Asdrúbal Aguilera-Méndez
- Institute of Biological Chemistry Research, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, México
| | | |
Collapse
|
8
|
Drzewoski J, Hanefeld M. The Current and Potential Therapeutic Use of Metformin-The Good Old Drug. Pharmaceuticals (Basel) 2021; 14:122. [PMID: 33562458 PMCID: PMC7915435 DOI: 10.3390/ph14020122] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 02/07/2023] Open
Abstract
Metformin, one of the oldest oral antidiabetic agents and still recommended by almost all current guidelines as the first-line treatment for type 2 diabetes mellitus (T2DM), has become the medication with steadily increasing potential therapeutic indications. A broad spectrum of experimental and clinical studies showed that metformin has a pleiotropic activity and favorable effect in different pathological conditions, including prediabetes, type 1 diabetes mellitus (T1DM) and gestational diabetes mellitus (GDM). Moreover, there are numerous studies, meta-analyses and population studies indicating that metformin is safe and well tolerated and may be associated with cardioprotective and nephroprotective effect. Recently, it has also been reported in some studies, but not all, that metformin, besides improvement of glucose homeostasis, may possibly reduce the risk of cancer development, inhibit the incidence of neurodegenerative disease and prolong the lifespan. This paper presents some arguments supporting the initiation of metformin in patients with newly diagnosed T2DM, especially those without cardiovascular risk factors or without established cardiovascular disease or advanced kidney insufficiency at the time of new guidelines favoring new drugs with pleotropic effects complimentary to glucose control. Moreover, it focuses on the potential beneficial effects of metformin in patients with T2DM and coexisting chronic diseases.
Collapse
Affiliation(s)
- Józef Drzewoski
- Central Teaching Hospital of Medical University of Lodz, 92-213 Lodz, Poland
| | - Markolf Hanefeld
- Medical Clinic III, Department of Medicine Technical University Dresden, 01307 Dresden, Germany;
| |
Collapse
|
9
|
Type II diabetes mellitus: a review on recent drug based therapeutics. Biomed Pharmacother 2020; 131:110708. [DOI: 10.1016/j.biopha.2020.110708] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/23/2020] [Accepted: 08/28/2020] [Indexed: 12/15/2022] Open
|
10
|
Biochemical adaptations in white adipose tissue following aerobic exercise: from mitochondrial biogenesis to browning. Biochem J 2020; 477:1061-1081. [PMID: 32187350 DOI: 10.1042/bcj20190466] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/24/2020] [Accepted: 02/28/2020] [Indexed: 02/07/2023]
Abstract
Our understanding of white adipose tissue (WAT) biochemistry has evolved over the last few decades and it is now clear that WAT is not simply a site of energy storage, but rather a pliable endocrine organ demonstrating dynamic responsiveness to the effects of aerobic exercise. Similar to its established effects in skeletal muscle, aerobic exercise induces many biochemical adaptations in WAT including mitochondrial biogenesis and browning. While past research has focused on the regulation of these biochemical processes, there has been renewed interest as of late given the potential of harnessing WAT mitochondrial biogenesis and browning to treat obesity and type II diabetes. Unfortunately, despite increasing evidence that innumerable factors, both exercise induced and pharmacological, can elicit these biochemical adaptations in WAT, the underlying mechanisms remain poorly defined. Here, we begin with a historical account of our understanding of WAT exercise biochemistry before presenting detailed evidence in favour of an up-to-date model by which aerobic exercise induces mitochondrial biogenesis and browning in WAT. Specifically, we discuss how aerobic exercise induces increases in WAT lipolysis and re-esterification and how this could be a trigger that activates the cellular energy sensor 5' AMP-activated protein kinase to mediate the induction of mitochondrial biogenesis and browning via the transcriptional co-activator peroxisome proliferator-activated receptor gamma co-activator-1 alpha. While this review primarily focuses on mechanistic results from rodent studies special attention is given to the translation of these results, or lack thereof, to human physiology.
Collapse
|
11
|
Malin SK, Stewart NR. Metformin May Contribute to Inter-individual Variability for Glycemic Responses to Exercise. Front Endocrinol (Lausanne) 2020; 11:519. [PMID: 32849302 PMCID: PMC7431621 DOI: 10.3389/fendo.2020.00519] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/26/2020] [Indexed: 12/20/2022] Open
Abstract
Metformin and exercise independently improve glycemic control. Metformin traditionally is considered to reduce hepatic glucose production, while exercise training is thought to stimulate skeletal muscle glucose disposal. Collectively, combining treatments would lead to the anticipation for additive glucose regulatory effects. Herein, we discuss recent literature suggesting that metformin may inhibit, enhance or have no effect on exercise mediated benefits toward glucose regulation, with particular emphasis on insulin sensitivity. Importantly, we address issues surrounding the impact of metformin on exercise induced glycemic benefit across multiple insulin sensitive tissues (e.g., skeletal muscle, liver, adipose, vasculature, and the brain) in effort to illuminate potential sources of inter-individual glycemic variation. Therefore, the review identifies gaps in knowledge that require attention in order to optimize medical approaches that improve care of people with elevated blood glucose levels and are at risk of cardiovascular disease.
Collapse
Affiliation(s)
- Steven K. Malin
- Department of Kinesiology, University of Virginia, Charlottesville, VA, United States
- Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, United States
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, United States
| | - Nathan R. Stewart
- Department of Kinesiology, University of Virginia, Charlottesville, VA, United States
| |
Collapse
|
12
|
Zhao J, Wu Y, Rong X, Zheng C, Guo J. Anti-Lipolysis Induced by Insulin in Diverse Pathophysiologic Conditions of Adipose Tissue. Diabetes Metab Syndr Obes 2020; 13:1575-1585. [PMID: 32494174 PMCID: PMC7227813 DOI: 10.2147/dmso.s250699] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 04/19/2020] [Indexed: 12/13/2022] Open
Abstract
As an important energy reservoir, adipose tissue maintains lipid balance and regulates energy metabolism. When the body requires energy, adipocytes provide fatty acids to peripheral tissues through lipolysis. Insulin plays an important role in regulating normal fatty acid levels by inhibiting lipolysis. When the morphology of adipose tissue is abnormal, its microenvironment changes and the lipid metabolic balance is disrupted, which seriously impairs insulin sensitivity. As the most sensitive organ to respond to insulin, lipolysis levels in adipose tissue are affected by impaired insulin function, which results in serious metabolic diseases. However, the specific underlying mechanisms of this process have not yet been fully elucidated, and further study is required. The purpose of this review is to discuss the effects of adipose tissue on the anti-lipolysis process triggered by insulin under different conditions. In particular, the functional changes of this process respond to inconsonantly morphological changes of adipose tissue.
Collapse
Affiliation(s)
- Jia Zhao
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
| | - YaYun Wu
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
| | - XiangLu Rong
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
- Guangdong TCM Key Laboratory for the Prevention and Treatment of Metabolic Diseases, Guangdong, People's Republic of China
- Joint Laboratory of Guangdong Province and Hong Kong and Macao Regions on Metabolic Diseases, Guangdong, People's Republic of China
| | - CuiWen Zheng
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
| | - Jiao Guo
- Guangdong Metabolic Diseases Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangdong, People's Republic of China
- Guangdong TCM Key Laboratory for the Prevention and Treatment of Metabolic Diseases, Guangdong, People's Republic of China
- Joint Laboratory of Guangdong Province and Hong Kong and Macao Regions on Metabolic Diseases, Guangdong, People's Republic of China
| |
Collapse
|
13
|
Kopietz F, Berggreen C, Larsson S, Säll J, Ekelund M, Sakamoto K, Degerman E, Holm C, Göransson O. AMPK activation by A-769662 and 991 does not affect catecholamine-induced lipolysis in human adipocytes. Am J Physiol Endocrinol Metab 2018; 315:E1075-E1085. [PMID: 30253109 DOI: 10.1152/ajpendo.00110.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Activation of AMP-activated protein kinase (AMPK) is considered an attractive strategy for the treatment of type 2 diabetes. Favorable metabolic effects of AMPK activation are mainly observed in skeletal muscle and liver tissue, whereas the effects in human adipose tissue are only poorly understood. Previous studies, which largely employed the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), suggest an antilipolytic role of AMPK in adipocytes. The aim of this work was to reinvestigate the role of AMPK in the regulation of lipolysis, using the novel allosteric small-molecule AMPK activators A-769662 and 991, with a focus on human adipocytes. For this purpose, human primary subcutaneous adipocytes were treated with A-769662, 991, or AICAR, as a control, before being stimulated with isoproterenol. AMPK activity status, glycerol release, and the phosphorylation of hormone-sensitive lipase (HSL), a key regulator of lipolysis, were then monitored. Our results show that both A-769662 and 991 activated AMPK to a level that was similar to, or greater than, that induced by AICAR. In contrast to AICAR, which as expected was antilipolytic, neither A-769662 nor 991 affected lipolysis in human adipocytes, although 991 treatment led to altered HSL phosphorylation. Furthermore, we suggest that HSL Ser660 is an important regulator of lipolytic activity in human adipocytes. These data suggest that the antilipolytic effect observed with AICAR in previous studies is, at least to some extent, AMPK independent.
Collapse
Affiliation(s)
- Franziska Kopietz
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | | | - Sara Larsson
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Johanna Säll
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Mikael Ekelund
- Surgery, Department of Clinical Sciences Malmö, Lund University , Malmö , Sweden
| | | | - Eva Degerman
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Cecilia Holm
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| | - Olga Göransson
- Department of Experimental Medical Science, Lund University , Lund , Sweden
| |
Collapse
|
14
|
Arner P, Kulyté A, Batchelor K, Laurencikiene J, Livingston J, Rydén M. Mapping of biguanide transporters in human fat cells and their impact on lipolysis. Diabetes Obes Metab 2018; 20:2416-2425. [PMID: 29862627 PMCID: PMC6133731 DOI: 10.1111/dom.13395] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 12/27/2022]
Abstract
AIM To examine the cell membrane transporters involved in mediating the antilipolytic effect of biguanides in human fat cells. MATERIALS AND METHODS Gene expression of biguanide transporters was mapped in human subcutaneous adipose tissue and in adipocytes before and after differentiation. Those expressed in mature fat cells were knocked down by RNA interference (RNAi) and the antilipolytic effects of metformin and two novel, highly potent biguanides, NT1014 and NT1044, were examined. RESULTS Analysis of the transporter affinity of biguanides in HEK293 cells overexpressing individual transporters showed that NT1014 and NT1044 had >10 times higher affinity than metformin. Animal studies showed that NT1014 was >5 times more potent than metformin in lowering plasma glucose in mice. In human fat cells, the novel biguanides displayed higher AMP-activated protein kinase activation and antilipolytic efficacy than metformin. Five transporters, organic cation transporter (OCT)1 (SLC22A1), organic cation transporter novel type 1 (OCTN1; SLC22A4), OCT3 (SLC22A3), plasma membrane monoamine transporter (PMAT; SLC29A4) and multidrug and toxin extrusion transporter (MATE1; SLC47A1), were detectable in fat cells but only OCT3, PMAT and MATE1 increased during adipogenesis in vitro and were enriched in fat cells compared with other adipose cell types. Gene knockdown by RNAi showed that MATE1 and PMAT reduction attenuated the antilipolytic effect of metformin but only PMAT knockdown decreased the effect of all three biguanides. CONCLUSIONS While human fat cells primarily express three biguanide transporters, our data suggest that PMAT is the primary target for development of fat cell-specific antilipolytic biguanides with high sensitivity and potency.
Collapse
Affiliation(s)
- Peter Arner
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86, Stockholm, Sweden
| | - Agné Kulyté
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86, Stockholm, Sweden
| | | | - Jurga Laurencikiene
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86, Stockholm, Sweden
| | - James Livingston
- NovaTarg Therapeutics Inc, Research Triangle Park, NC 27709, USA
| | - Mikael Rydén
- Department of Medicine (H7), Karolinska Institutet, Karolinska University Hospital, Huddinge, 141 86, Stockholm, Sweden
| |
Collapse
|
15
|
Wang Y, Meng Y, Zhang S, Wu H, Yang D, Nie C, Hu Q. Phenformin and metformin inhibit growth and migration of LN229 glioma cells in vitro and in vivo. Onco Targets Ther 2018; 11:6039-6048. [PMID: 30275708 PMCID: PMC6157995 DOI: 10.2147/ott.s168981] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Background Malignant glioma is refractory to conventional treatment, highlighting a need to develop novel efficacious therapies. Biguanides, a class of oral antidiabetic drug, have been thought to inhibit proliferation and metastasis in a variety of cancers. Purpose The objective of this study was to investigate the affections of biguanides, phenformin (Phen) and metformin (Met), on growth and migration of glioma cells LN229 in vitro and in vivo. Methods Glioma cells LN229 were treated with Phen or Met, then cell proliferation and death were evaluated by MTT assay and PI stain, and cell cycle were evaluated using flow cytometric analysis, meantime wound healing assay and transwell migration assay were performed to detect cell migration ability. In addition, LN229 were injected in thigh of nude mice, and the mice were treated with Phen or Met to detect the effect of Phen and Met in vivo. Results Phen and Met could significantly inhibit cell growth through inhibiting cell proliferation, promoting cell death and disturbing cell cycle, and these drugs also could inhibit cell colony formation in glioma cells LN229 in vitro. Meanwhile, both Phen and Met could significantly inhibit cell migration of LN229 in vitro, through effecting the expression of E-cadherin and Vimentin. In addition, both Phen and Met inhibited the growth and migration of LN229 in a tumor xenograft model. Furthermore, Phen and Met were associated with the increased level of ROS of cell mitochondrial, and ROS inhibitor NAC could significantly rescue the cell death induced by Phen and Met. Conclusion Phen and Met displayed powerful antitumor effects of LN229, and our findings powerfully suggest the possibility of Phen and Met being used as an adjuvant agent in the treatment of glioma patients.
Collapse
Affiliation(s)
- Yanmin Wang
- Department of Cerebral Surgery, Tianjin Beichen Hospital, Tianjin 300000, People's Republic of China,
| | - Yanli Meng
- Library, Tianjin Medical University, Tianjin 300000, People's Republic of China
| | - Shijun Zhang
- Department of Cerebral Surgery, Tianjin Beichen Hospital, Tianjin 300000, People's Republic of China,
| | - Huancheng Wu
- Department of Cerebral Surgery, Tianjin Beichen Hospital, Tianjin 300000, People's Republic of China,
| | - Dawei Yang
- Department of Cerebral Surgery, Tianjin Beichen Hospital, Tianjin 300000, People's Republic of China,
| | - Chaohui Nie
- Department of Cerebral Surgery, Tianjin Beichen Hospital, Tianjin 300000, People's Republic of China,
| | - Qunliang Hu
- Department of Cerebral Surgery, Tianjin Beichen Hospital, Tianjin 300000, People's Republic of China,
| |
Collapse
|
16
|
Krauzová E, Tůma P, de Glisezinski I, Štich V, Šiklová M. Metformin Does Not Inhibit Exercise-Induced Lipolysis in Adipose Tissue in Young Healthy Lean Men. Front Physiol 2018; 9:604. [PMID: 29875699 PMCID: PMC5974160 DOI: 10.3389/fphys.2018.00604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/04/2018] [Indexed: 01/04/2023] Open
Abstract
Objective: Metformin was shown to exert an antilipolytic action in adipose tissue (AT) that might mediate beneficial effects on lipid metabolism in diabetic patients. However, during exercise, the inhibition of induced lipolysis in AT would limit the energy substrate supply for working muscle. Thus, the aim of this study was to investigate whether metformin exerts inhibitory effect on exercise-induced lipolysis in subcutaneous adipose tissue (SCAT) (Moro et al., 2007) in humans. Approach: Ten healthy lean men underwent two exercise sessions consisting of 60 min of cycling on bicycle ergometer combined with (a) orally administered metformin and (b) metformin locally administered into SCAT. Microdialysis was used to assess lipolysis in situ in SCAT. Glycerol, metformin and lactate were measured in dialysate and plasma by enzyme colorimetric kits and capillary electrophoresis. Results: Metformin levels increased continuously in plasma during 3 h after oral administration, and peaked after 3.5 h (peak concentration 4 μg/ml). Metformin was detected in dialysate outflowing from SCAT and showed a similar time-course as that in plasma with the peak concentration of 1.3 μg/ml. The lipolytic rate in SCAT (assessed as glycerol release) increased in response to exercise (4.3 ± 0.5-fold vs. basal; p = 0.002) and was not suppressed either by local or oral metformin administration. The lactate levels increased in plasma and in dialysate from SCAT after 30-60 min of exercise (3.6-fold vs. basal; p = 0.015; 2.75-fold vs. basal; p = 0.002, respectively). No effect of metformin on lactate levels in SCAT dialysate or in plasma during exercise was observed. Conclusion: Metformin did not reduce the exercise-induced lipolysis in SCAT. This suggests that metformin administration does not interfere with the lipid mobilization and energy substrate provision during physical activity.
Collapse
Affiliation(s)
- Eva Krauzová
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia.,Second Department of Internal Medicine, University Hospital Královské Vinohrady, Prague, Czechia
| | - Petr Tůma
- Department of Hygiene, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Isabelle de Glisezinski
- INSERM, UMR1048, Obesity Research Laboratory, Institute of Metabolic and Cardiovascular Diseases, University of Toulouse, Paul Sabatier University, Toulouse, France.,Department of Clinical Biochemistry and Sports Medicine, Toulouse University Hospital, Toulouse, France
| | - Vladimír Štich
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia.,Second Department of Internal Medicine, University Hospital Královské Vinohrady, Prague, Czechia
| | - Michaela Šiklová
- Department for the Study of Obesity and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czechia
| |
Collapse
|
17
|
Sulforaphane attenuates bisphenol A-induced 3T3-L1 adipocyte differentiation through cell cycle arrest. J Funct Foods 2018. [DOI: 10.1016/j.jff.2018.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
|
18
|
Esquejo RM, Salatto CT, Delmore J, Albuquerque B, Reyes A, Shi Y, Moccia R, Cokorinos E, Peloquin M, Monetti M, Barricklow J, Bollinger E, Smith BK, Day EA, Nguyen C, Geoghegan KF, Kreeger JM, Opsahl A, Ward J, Kalgutkar AS, Tess D, Butler L, Shirai N, Osborne TF, Steinberg GR, Birnbaum MJ, Cameron KO, Miller RA. Activation of Liver AMPK with PF-06409577 Corrects NAFLD and Lowers Cholesterol in Rodent and Primate Preclinical Models. EBioMedicine 2018; 31:122-132. [PMID: 29673898 PMCID: PMC6014578 DOI: 10.1016/j.ebiom.2018.04.009] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/26/2018] [Accepted: 04/06/2018] [Indexed: 12/28/2022] Open
Abstract
Dysregulation of hepatic lipid and cholesterol metabolism is a significant contributor to cardiometabolic health, resulting in excessive liver lipid accumulation and ultimately non-alcoholic steatohepatitis (NASH). Therapeutic activators of the AMP-Activated Protein Kinase (AMPK) have been proposed as a treatment for metabolic diseases; we show that the AMPK β1-biased activator PF-06409577 is capable of lowering hepatic and systemic lipid and cholesterol levels in both rodent and monkey preclinical models. PF-06409577 is able to inhibit de novo lipid and cholesterol synthesis pathways, and causes a reduction in hepatic lipids and mRNA expression of markers of hepatic fibrosis. These effects require AMPK activity in the hepatocytes. Treatment of hyperlipidemic rats or cynomolgus monkeys with PF-06409577 for 6 weeks resulted in a reduction in circulating cholesterol. Together these data suggest that activation of AMPK β1 complexes with PF-06409577 is capable of impacting multiple facets of liver disease and represents a promising strategy for the treatment of NAFLD and NASH in humans. PF-06409577 is a potent activator of AMPK β1 containing complexes. PF-06409577 improves liver function and systemic dyslipidemia in rodents through hepatic AMPK activation. PF-06409577-mediated reductions in circulating cholesterol was observed in monkeys and diabetic rats.
NAFLD and NASH remain poorly treated and are diseases which are growing rapidly in societal cost. Therapeutic mechanisms that impact multiple aspects of the dysregulated metabolic regulation of NAFLD and NASH are needed. Pharmacological AMPK activation has long held promise as a treatment for NAFLD because of its impact on hepatic lipid and cholesterol synthesis, as well as its proposed anti-inflammatory and anti-lipolytic actions. Recent development of clinically viable small molecule AMPK activators, including PF-06409577, has enabled their more thorough characterization in preclinical disease models.
Collapse
Affiliation(s)
- Ryan M Esquejo
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | | | - Jake Delmore
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | | | - Allan Reyes
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | - Yuji Shi
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | - Rob Moccia
- Computational Sciences, Pfizer Inc, Cambridge, MA, USA
| | - Emily Cokorinos
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | | | - Mara Monetti
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | - Jason Barricklow
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc, Groton, CT, USA
| | - Eliza Bollinger
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | - Brennan K Smith
- Division of Endocrinology and Metabolism, Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W., Hamilton, ON L8N 3Z5, Canada
| | - Emily A Day
- Division of Endocrinology and Metabolism, Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W., Hamilton, ON L8N 3Z5, Canada
| | - Chuong Nguyen
- Primary Pharmacology Group, Pfizer Inc, Groton, CT, USA
| | | | - John M Kreeger
- Drug Safety Research and Development, Pfizer Inc, Groton, CT, USA
| | - Alan Opsahl
- Drug Safety Research and Development, Pfizer Inc, Groton, CT, USA
| | - Jessica Ward
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA
| | - Amit S Kalgutkar
- Sanford Burnham Prebys Medical Discovery Institute, 6400 Sanger Road, Orlando, FL 32827, USA
| | - David Tess
- Sanford Burnham Prebys Medical Discovery Institute, 6400 Sanger Road, Orlando, FL 32827, USA
| | - Lynne Butler
- Drug Safety Research and Development, Pfizer Inc, Groton, CT, USA
| | - Norimitsu Shirai
- Drug Safety Research and Development, Pfizer Inc, Groton, CT, USA
| | - Timothy F Osborne
- Sanford Burnham Prebys Medical Discovery Institute, 6400 Sanger Road, Orlando, FL 32827, USA
| | - Gregory R Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine and Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main St. W., Hamilton, ON L8N 3Z5, Canada
| | | | | | - Russell A Miller
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, MA, USA.
| |
Collapse
|
19
|
Abstract
Adipose tissue represents a critical component in healthy energy homeostasis. It fulfills important roles in whole-body lipid handling, serves as the body's major energy storage compartment and insulation barrier, and secretes numerous endocrine mediators such as adipokines or lipokines. As a consequence, dysfunction of these processes in adipose tissue compartments is tightly linked to severe metabolic disorders, including obesity, metabolic syndrome, lipodystrophy, and cachexia. While numerous studies have addressed causes and consequences of obesity-related adipose tissue hypertrophy and hyperplasia for health, critical pathways and mechanisms in (involuntary) adipose tissue loss as well as its systemic metabolic consequences are far less understood. In this review, we discuss the current understanding of conditions of adipose tissue wasting and review microenvironmental determinants of adipocyte (dys)function in related pathophysiologies.
Collapse
Affiliation(s)
- Alexandros Vegiopoulos
- Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center (DKFZ) Heidelberg, Heidelberg, Germany
| | - Maria Rohm
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Stephan Herzig
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Joint Heidelberg-IDC Translational Diabetes Program Inner Medicine I, Neuherberg, Germany
| |
Collapse
|
20
|
Tanveer A, Akram K, Farooq U, Hayat Z, Shafi A. Management of diabetic complications through fruit flavonoids as a natural remedy. Crit Rev Food Sci Nutr 2017; 57:1411-1422. [PMID: 26065867 DOI: 10.1080/10408398.2014.1000482] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diabetes mellitus is a global disorder, and a major issue for health care systems. The current review outlooks the use of fruit flavonoids as natural remedy in the prevention of diabetes mellitus. The onset of diabetes mainly depends upon genetics and lifestyle issues. Currently used therapeutic options for the control of diabetes, like dietary amendments, oral hypoglycemic drugs, and insulin, have their own limitations. Fruit flavonoids possess various antidiabetic, anti-inflammatory, and antioxidant potentials and act on various cellular signaling pathways in pancreas, white adipose tissue, skeletal muscle, and liver function, which in result induces antidiabetic effects. Recently, antidiabetic effect of fruit flavonoids has been studied using various animal models and clinical trials. Research studies revealed a statistically significant potential of fruit flavonoids in managing the altered glucose and oxidative metabolisms in diabetes. Unlike synthetic antidiabetic agents, fruit flavonoids manage diabetes without compromising cellular homeostasis thereby posing no side effects. Further studies are required in purification and characterization of different fruit flavonoids with respect to their beneficial effect for diabetic patients.
Collapse
Affiliation(s)
- Amna Tanveer
- a Institute of Food Science and Nutrition, University of Sargodha , Sargodha , Pakistan
| | - Kashif Akram
- a Institute of Food Science and Nutrition, University of Sargodha , Sargodha , Pakistan
| | - Umar Farooq
- a Institute of Food Science and Nutrition, University of Sargodha , Sargodha , Pakistan
| | - Zafar Hayat
- b Department of Animal Sciences , University College of Agriculture, University of Sargodha , Sargodha , Pakistan
| | - Afshan Shafi
- a Institute of Food Science and Nutrition, University of Sargodha , Sargodha , Pakistan
| |
Collapse
|
21
|
Rohm M, Schäfer M, Laurent V, Üstünel BE, Niopek K, Algire C, Hautzinger O, Sijmonsma TP, Zota A, Medrikova D, Pellegata NS, Ryden M, Kulyte A, Dahlman I, Arner P, Petrovic N, Cannon B, Amri EZ, Kemp BE, Steinberg GR, Janovska P, Kopecky J, Wolfrum C, Blüher M, Berriel Diaz M, Herzig S. An AMP-activated protein kinase-stabilizing peptide ameliorates adipose tissue wasting in cancer cachexia in mice. Nat Med 2016; 22:1120-1130. [PMID: 27571348 DOI: 10.1038/nm.4171] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 07/27/2016] [Indexed: 12/17/2022]
Abstract
Cachexia represents a fatal energy-wasting syndrome in a large number of patients with cancer that mostly results in a pathological loss of skeletal muscle and adipose tissue. Here we show that tumor cell exposure and tumor growth in mice triggered a futile energy-wasting cycle in cultured white adipocytes and white adipose tissue (WAT), respectively. Although uncoupling protein 1 (Ucp1)-dependent thermogenesis was dispensable for tumor-induced body wasting, WAT from cachectic mice and tumor-cell-supernatant-treated adipocytes were consistently characterized by the simultaneous induction of both lipolytic and lipogenic pathways. Paradoxically, this was accompanied by an inactivated AMP-activated protein kinase (Ampk), which is normally activated in peripheral tissues during states of low cellular energy. Ampk inactivation correlated with its degradation and with upregulation of the Ampk-interacting protein Cidea. Therefore, we developed an Ampk-stabilizing peptide, ACIP, which was able to ameliorate WAT wasting in vitro and in vivo by shielding the Cidea-targeted interaction surface on Ampk. Thus, our data establish the Ucp1-independent remodeling of adipocyte lipid homeostasis as a key event in tumor-induced WAT wasting, and we propose the ACIP-dependent preservation of Ampk integrity in the WAT as a concept in future therapies for cachexia.
Collapse
Affiliation(s)
- Maria Rohm
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Michaela Schäfer
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Victor Laurent
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Bilgen Ekim Üstünel
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Katharina Niopek
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Carolyn Algire
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
| | - Oksana Hautzinger
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
| | - Tjeerd P Sijmonsma
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
| | - Annika Zota
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Dasa Medrikova
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
| | - Natalia S Pellegata
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Mikael Ryden
- Lipid Laboratory, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Agné Kulyte
- Lipid Laboratory, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Ingrid Dahlman
- Lipid Laboratory, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Peter Arner
- Lipid Laboratory, Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Natasa Petrovic
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Ez-Zoubir Amri
- Université Côte d'Azur, Nice, France.,Centre National de la Recherche Scientifique (CNRS), Nice, France
| | - Bruce E Kemp
- St Vincent's Institute of Medical Research, University of Melbourne, Fitzroy, Victoria, Australia.,Mary MacKillop Institute for Health, Research Australian Catholic University, Melbourne, Victoria, Australia
| | - Gregory R Steinberg
- Department of Medicine, Division of Endocrinology and Metabolism, McMaster University, Hamilton, Ontario, Canada
| | - Petra Janovska
- Department of Adipose Tissue Biology, Institute of Physiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jan Kopecky
- Department of Adipose Tissue Biology, Institute of Physiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Christian Wolfrum
- Swiss Federal Institute of Technology, Institute of Food Nutrition and Health, Schwerzenbach, Switzerland
| | - Matthias Blüher
- Department of Medicine, University of Leipzig, Leipzig, Germany
| | - Mauricio Berriel Diaz
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| | - Stephan Herzig
- Institute for Diabetes and Cancer (IDC), Helmholtz Center Munich, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany.,Deutsches Zentrum für Diabetesforschung, Neuherberg, Germany
| |
Collapse
|
22
|
Rana H, Yadav SS, Reddy HD, Singhal S, Singh DK, Usman K. Comparative Effect of Insulin Sensitizers and Statin on Metabolic Profile and Ultrasonographical Score in Non Alcoholic Fatty Liver Disease. J Clin Diagn Res 2016; 10:OC19-23. [PMID: 27656480 DOI: 10.7860/jcdr/2016/19887.8336] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/27/2016] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Non Alcoholic Fatty Liver Disease (NAFLD) is a metabolic disorder involving fat accumulation in the liver. The initial management for patients with NAFLD includes lifestyle modification and weight loss in overweight or obese patients. AIM The present study was conducted to compare the efficacy of insulin sensitizers and statin in the patients of NAFLD. MATERIALS AND METHODS The study included 98 patients diagnosed with NAFLD on USG (Ultrasonography) abdomen, divided into three Groups randomly and administered Metformin (Group I), Rosuvastatin (Group II) or Pioglitazone (Group III) along with dietary intervention and lifestyle modification. Their Body Mass Index (BMI), liver function tests, fasting lipid profile, USG scores for fatty liver were done and followed up at 4 weeks, 12 weeks and 24 week for change in above parameters. RESULTS Out of the three Groups, Group II showed a maximum improvements in usg scores for NAFLD (p<0.001) and fasting lipid profile. Group II also showed maximum derangement of liver enzymes at 24 weeks though none of the subjects had more than three times elevation of liver enzymes. CONCLUSION Rosuvastatin may be an effective therapy as add on treatment to dietary and lifestyle intervention in patients of NAFLD. As an add-on treatment Rosuvastatin was superior to Pioglitazone or Metformin and acute decompensation is unlikely with this drug. Metformin was not effective as add on therapy for NAFLD, rather rapid weight loss in short period of time resulted in worsening of hepatic steatosis.
Collapse
Affiliation(s)
- Himanshu Rana
- Junior Resident, Department of Medicine, King George's Medical University , Lucknow, Uttar Pradesh, India
| | - Suraj Singh Yadav
- Senior Resident, Department of Pharmacology, King George's Medical University , Lucknow, Uttar Pradesh, India
| | - Himanshu D Reddy
- Associate Professor, Department of Medicine, King George's Medical University , Lucknow, Uttar Pradesh, India
| | - Shubham Singhal
- Junior Resident, Department of Medicine, King George's Medical University , Lucknow, Uttar Pradesh, India
| | - Dinesh Kumar Singh
- Junior Resident, Department of Medicine, King George's Medical University , Lucknow, Uttar Pradesh, India
| | - Kauser Usman
- Professor, Department of Medicine, King George's Medical University , Lucknow, Uttar Pradesh, India
| |
Collapse
|
23
|
Tebbe C, Chhina J, Dar SA, Sarigiannis K, Giri S, Munkarah AR, Rattan R. Metformin limits the adipocyte tumor-promoting effect on ovarian cancer. Oncotarget 2015; 5:4746-64. [PMID: 24970804 PMCID: PMC4148096 DOI: 10.18632/oncotarget.2012] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Omental adipocytes promote ovarian cancer by secretion of adipokines, cytokines and growth factors, and acting as fuel depots. We investigated if metformin modulates the ovarian cancer promoting effects of adipocytes. Effect of conditioned media obtained from differentiated mouse 3T3L1 preadipoctes on the proliferation and migration of a mouse ovarian surface epithelium cancer cell line (ID8) was estimated. Conditioned media from differentiated adipocytes increased the proliferation and migration of ID8 cells, which was attenuated by metformin. Metformin inhibited adipogenesis by inhibition of key adipogenesis regulating transcription factors (CEBPα, CEBPß, and SREBP1), and induced AMPK. A targeted Cancer Pathway Finder RT-PCR (real-time polymerase chain reaction) based gene array revealed 20 up-regulated and 2 down-regulated genes in ID8 cells exposed to adipocyte conditioned media, which were altered by metformin. Adipocyte conditioned media also induced bio-energetic changes in the ID8 cells by pushing them into a highly metabolically active state; these effects were reversed by metformin. Collectively, metformin treatment inhibited the adipocyte mediated ovarian cancer cell proliferation, migration, expression of cancer associated genes and bio-energetic changes. Suggesting, that metformin could be a therapeutic option for ovarian cancer at an early stage, as it not only targets ovarian cancer, but also modulates the environmental milieu.
Collapse
Affiliation(s)
- Calvin Tebbe
- Division of Gynecology Oncology, Department of Women's Health, Obstetrics and Gynecology, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Jasdeep Chhina
- Division of Gynecology Oncology, Department of Women's Health, Obstetrics and Gynecology, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Sajad A Dar
- Division of Gynecology Oncology, Department of Women's Health, Obstetrics and Gynecology, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Kalli Sarigiannis
- Division of Gynecology Oncology, Department of Women's Health, Obstetrics and Gynecology, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Shailendra Giri
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Adnan R Munkarah
- Division of Gynecology Oncology, Department of Women's Health, Obstetrics and Gynecology, Henry Ford Hospital, Detroit, MI 48202, USA
| | - Ramandeep Rattan
- Division of Gynecology Oncology, Department of Women's Health, Obstetrics and Gynecology, Henry Ford Hospital, Detroit, MI 48202, USA
| |
Collapse
|
24
|
Wu Y, Song P, Zhang W, Liu J, Dai X, Liu Z, Lu Q, Ouyang C, Xie Z, Zhao Z, Zhuo X, Viollet B, Foretz M, Wu J, Yuan Z, Zou MH. Activation of AMPKα2 in adipocytes is essential for nicotine-induced insulin resistance in vivo. Nat Med 2015; 21:373-82. [PMID: 25799226 PMCID: PMC4390501 DOI: 10.1038/nm.3826] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/17/2015] [Indexed: 12/15/2022]
Abstract
Cigarette smoking promotes body weight reduction in humans while paradoxically also promoting insulin resistance (IR) and hyperinsulinemia. However, the mechanisms behind these effects are unclear. Here we show that nicotine, a major constituent of cigarette smoke, selectively activates AMP-activated protein kinase α2 (AMPKα2) in adipocytes, which in turn phosphorylates MAP kinase phosphatase-1 (MKP1) at serine 334, initiating its proteasome-dependent degradation. The nicotine-dependent reduction of MKP1 induces the aberrant activation of both p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, leading to increased phosphorylation of insulin receptor substrate 1 (IRS1) at serine 307. Phosphorylation of IRS1 leads to its degradation, protein kinase B inhibition, and the loss of insulin-mediated inhibition of lipolysis. Consequently, nicotine increases lipolysis, which results in body weight reduction, but this increase also elevates the levels of circulating free fatty acids and thus causes IR in insulin-sensitive tissues. These results establish AMPKα2 as an essential mediator of nicotine-induced whole-body IR in spite of reductions in adiposity.
Collapse
Affiliation(s)
- Yue Wu
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ping Song
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Wencheng Zhang
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Junhui Liu
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiaoyan Dai
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Zhaoyu Liu
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Qiulun Lu
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Changhan Ouyang
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Zhonglin Xie
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Zhengxing Zhao
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Xiaozhen Zhuo
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Benoit Viollet
- 1] INSERM, U1016, Institut Cochin, Paris, France. [2] CNRS, UMR 8104, Paris, France. [3] Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marc Foretz
- 1] INSERM, U1016, Institut Cochin, Paris, France. [2] CNRS, UMR 8104, Paris, France. [3] Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jiliang Wu
- Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Zuyi Yuan
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ming-Hui Zou
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
| |
Collapse
|
25
|
Abstract
OBJECTIVE Although elevated free fatty acid (FFA) levels in obesity have been considered to be of importance for insulin resistance, a recent meta-analysis suggested normal FFA levels in obese subjects. We investigated fasting circulating FFA and glycerol levels in a large cohort of non-obese and obese subjects. METHODS Subjects recruited for a study on obesity genetics were investigated in the morning after an overnight fast (n = 3,888). Serum FFA (n = 3,306), plasma glycerol (n = 3,776), and insulin sensitivity index (HOMA-IR,n = 3,469) were determined. Obesity was defined as BMI ≥ 30 kg/m 2 and insulin resistance as HOMA-IR ≥ 2.21. RESULTS In obese subjects, circulating FFA and glycerol levels were higher than in non-obese individuals (by 26% and 47%, respectively; both p < 0.0001). Similar results were obtained if only men, women or medication-free subjects were investigated. Insulin resistance and type 2 diabetes were associated with a further minor increase in FFA/glycerol among obese subjects. When comparing insulin-sensitive non-obese with insulin-sensitive or -resistant obese individuals, FFA and glycerol were 21–29% and 43–49% higher in obese individuals, respectively. CONCLUSION Circulating FFA and glycerol levels are markedly elevated in obesity but only marginally influenced by insulin resistance and type 2 diabetes. Whether these differences persist during diurnal variations in circulating FFA/glycerol, remains to be established
Collapse
Affiliation(s)
| | - Mikael Rydén
- *Prof. Dr. Dr. Mikael Rydén, C2-94, Karolinska Institutet, Department of Medicine (H7) and, Division of Endocrinology and Metabolism, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden,
| |
Collapse
|
26
|
Rahimi Naini S, Fuchs M. Non-alcoholic fatty liver disease in patients with diabetes mellitus. Expert Rev Endocrinol Metab 2014; 9:503-514. [PMID: 30736212 DOI: 10.1586/17446651.2014.938053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD), including the disease stages steatosis and non-alcoholic steatohepatitis, is the most common cause of chronic liver disease worldwide and linked to the epidemic of diabetes mellitus and obesity. It is characterized by a high cardiovascular and liver-related mortality and expected to be the leading cause for liver transplantation in the near future. This review summarizes recent progress made in our understanding of the disease pathogenesis and the clinical management of patients with NAFLD. Strategies to manage diabetes mellitus will be evaluated in terms of their effectiveness in treating patients with NAFLD and novel pharmacological targets capable to treat diabetes mellitus and NAFLD will be highlighted.
Collapse
Affiliation(s)
- Sohrab Rahimi Naini
- a Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University Medical Center, Richmond, VA, USA
| | - Michael Fuchs
- a Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University Medical Center, Richmond, VA, USA
- b Hunter Holmes McGuire Department of Veterans Affairs Medical Center, Gastrointestinal and Hepatology Service, (111-N) McGuire DVAMC, 1201 Broad Rock Boulevard, Richmond, VA, USA
| |
Collapse
|
27
|
Fruci B, Giuliano S, Mazza A, Malaguarnera R, Belfiore A. Nonalcoholic Fatty liver: a possible new target for type 2 diabetes prevention and treatment. Int J Mol Sci 2013; 14:22933-66. [PMID: 24264040 PMCID: PMC3856099 DOI: 10.3390/ijms141122933] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/30/2013] [Accepted: 11/08/2013] [Indexed: 12/12/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder worldwide. Several lines of evidence have indicated a pathogenic role of insulin resistance, and a strong association with type 2 diabetes (T2MD) and metabolic syndrome. Importantly, NAFLD appears to enhance the risk for T2MD, as well as worsen glycemic control and cardiovascular disease in diabetic patients. In turn, T2MD may promote NAFLD progression. The opportunity to take into account NAFLD in T2MD prevention and care has stimulated several clinical studies in which antidiabetic drugs, such as metformin, thiazolidinediones, GLP-1 analogues and DPP-4 inhibitors have been evaluated in NAFLD patients. In this review, we provide an overview of preclinical and clinical evidences on the possible efficacy of antidiabetic drugs in NAFLD treatment. Overall, available data suggest that metformin has beneficial effects on body weight reduction and metabolic parameters, with uncertain effects on liver histology, while pioglitazone may improve liver histology. Few data, mostly preclinical, are available on DPP4 inhibitors and GLP-1 analogues. The heterogeneity of these studies and the small number of patients do not allow for firm conclusions about treatment guidelines, and further randomized, controlled studies are needed.
Collapse
Affiliation(s)
- Barbara Fruci
- Endocrinology, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy.
| | | | | | | | | |
Collapse
|
28
|
Gesmundo I, Gallo D, Favaro E, Ghigo E, Granata R. Obestatin: a new metabolic player in the pancreas and white adipose tissue. IUBMB Life 2013; 65:976-82. [PMID: 24217898 DOI: 10.1002/iub.1226] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/10/2013] [Accepted: 10/11/2013] [Indexed: 01/14/2023]
Abstract
Obestatin is a 23 amino acid amidated peptide, member of the preproghrelin gene-derived peptides. Initially, obestatin was reported to exert opposite effects to those of ghrelin on food intake and body weight gain, through interaction with GPR39; however, these findings are still strongly debated and obestatin biological role remains largely unknown. Interestingly, binding of obestatin to the glucagon-like peptide 1 receptor has been recently suggested. Despite being a controversial peptide, recent findings have clearly indicated that obestatin is indeed a multifunctional peptide, exerting a variety of effects, such as stimulation of cell proliferation, survival and differentiation, influence on glucose and lipid metabolism, as well as anti-inflammatory and cardioprotective actions. Its positive effects on glucose and lipid metabolism candidate this peptide as a potential therapeutic tool in pathological conditions such as insulin resistance and diabetes.
Collapse
Affiliation(s)
- Iacopo Gesmundo
- Division of Endocrinology, Diabetology and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
| | | | | | | | | |
Collapse
|
29
|
Lettieri Barbato D, Tatulli G, Aquilano K, Ciriolo MR. FoxO1 controls lysosomal acid lipase in adipocytes: implication of lipophagy during nutrient restriction and metformin treatment. Cell Death Dis 2013; 4:e861. [PMID: 24136225 PMCID: PMC3920962 DOI: 10.1038/cddis.2013.404] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/11/2013] [Accepted: 09/13/2013] [Indexed: 12/21/2022]
Abstract
Finding new molecular pathways and strategies modulating lipolysis in adipocytes is an attractive goal of the current research. Indeed, it is becoming clear that several human age-related pathologies are caused by adipose tissue expansion and altered lipid metabolism. In the present work, we show that transcription factor forkhead homeobox type protein O1 (FoxO1) is upregulated by nutrient restriction (NR) in adipocytes and exerts the transcriptional control of lipid catabolism via the induction of lysosomal acid lipase (Lipa). An increased autophagy and colocalization of lipid droplets (LDs) with lysosomes was observed implying lipophagy in Lipa-mediated LDs degradation. Interestingly, we found that metformin (Metf), a biguanide drug commonly used to treat type-2 diabetes, exerts effects comparable to that of NR. Actually, it was able to elicit FoxO1-dependent Lipa induction as well as LDs degradation through lipophagy. Moreover, we demonstrate that, during NR or Metf treatment, free fatty acids released by Lipa are directed toward AMP-activated protein kinase-mediated mitochondrial oxidation, thus maintaining energetic homeostasis in adipocytes. In conclusion, our data show that lysosomal-mediated lipid catabolism is activated by NR in adipocytes and give further support to the use of Metf as a NR mimetic to combat age-related diseases associated with altered lipid metabolism.
Collapse
Affiliation(s)
- D Lettieri Barbato
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica, Rome 00133, Italy
| | | | | | | |
Collapse
|
30
|
Huang Z, Wan X, Liu J, Deng W, Chen A, Liu L, Liu J, Wei G, Li H, Fang D, Li Y. Short-term continuous subcutaneous insulin infusion combined with insulin sensitizers rosiglitazone, metformin, or antioxidant α-lipoic acid in patients with newly diagnosed type 2 diabetes mellitus. Diabetes Technol Ther 2013; 15:859-69. [PMID: 23991629 PMCID: PMC3781121 DOI: 10.1089/dia.2013.0013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Short-term continuous subcutaneous insulin infusion (CSII) in patients with newly diagnosed type 2 diabetes has been proved effective in improving metabolic control and β-cell function, thus inducing long-term drug-free remission. A randomized controlled trial was conducted to investigate whether CSII in combination with rosiglitazone, metformin, or α-lipoic acid separately brings about extra benefits. PATIENTS AND METHODS One hundred sixty patients with newly diagnosed type 2 diabetes were randomized to one of four treatment groups: CSII alone, CSII in combination with rosiglitazone or metformin for 3 months, or CSII with α-lipoic acid intravenous infusion for 2 weeks. Duration of CSII treatment was identical in the four groups. Glucose and lipid profiles, homeostasis model assessment (HOMA) indices, acute insulin response (AIR), intramyocellular lipid (IMCL) level, and malondialdehyde level were compared before and after intervention. RESULTS The near-normoglycemia rate at the third month in CSII alone and that in combination with rosiglitazone, metformin, or α-lipoic acid was 72.5%, 87.5%, 90%, and 75%, respectively (metformin group vs. CSII alone, P=0.045). The metformin group achieved euglycemia in a shorter time (2.6 ± 1.3 vs. 3.7 ± 1.8 days, P=0.020) with less daily insulin dosage and was more powerful in lowering total cholesterol, increasing AIR and HOMA β-cell function, whereas reduction of IMCL in the soleus was more obvious in the rosiglitazone group but not in the metformin group. The efficacy of combination with α-lipoic acid was similar to that of CSII alone. CONCLUSIONS Short-term CSII in combination with rosiglitazone or metformin is superior to CSII alone, yet the efficacy of the two differs in some way, whereas that with α-lipoic acid might not have an additive effect.
Collapse
Affiliation(s)
- Zhimin Huang
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University , Guangzhou, Guangdong, People's Republic of China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Role of AMP-activated protein kinase in adipose tissue metabolism and inflammation. Clin Sci (Lond) 2013; 124:491-507. [PMID: 23298225 DOI: 10.1042/cs20120536] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AMPK (AMP-activated protein kinase) is a key regulator of cellular and whole-body energy balance. AMPK phosphorylates and regulates many proteins concerned with nutrient metabolism, largely acting to suppress anabolic ATP-consuming pathways while stimulating catabolic ATP-generating pathways. This has led to considerable interest in AMPK as a therapeutic target for the metabolic dysfunction observed in obesity and insulin resistance. The role of AMPK in skeletal muscle and the liver has been extensively studied, such that AMPK has been demonstrated to inhibit synthesis of fatty acids, cholesterol and isoprenoids, hepatic gluconeogenesis and translation while increasing fatty acid oxidation, muscle glucose transport, mitochondrial biogenesis and caloric intake. The role of AMPK in the other principal metabolic and insulin-sensitive tissue, adipose, remains poorly characterized in comparison, yet increasing evidence supports an important role for AMPK in adipose tissue function. Obesity is characterized by hypertrophy of adipocytes and the development of a chronic sub-clinical pro-inflammatory environment in adipose tissue, leading to increased infiltration of immune cells. This combination of dysfunctional hypertrophic adipocytes and a pro-inflammatory environment contributes to insulin resistance and the development of Type 2 diabetes. Exciting recent studies indicate that AMPK may not only influence metabolism in adipocytes, but also act to suppress this pro-inflammatory environment, such that targeting AMPK in adipose tissue may be desirable to normalize adipose dysfunction and inflammation. In the present review, we discuss the role of AMPK in adipose tissue, focussing on the regulation of carbohydrate and lipid metabolism, adipogenesis and pro-inflammatory pathways in physiological and pathophysiological conditions.
Collapse
|
32
|
O'Neill HM, Holloway GP, Steinberg GR. AMPK regulation of fatty acid metabolism and mitochondrial biogenesis: implications for obesity. Mol Cell Endocrinol 2013; 366:135-51. [PMID: 22750049 DOI: 10.1016/j.mce.2012.06.019] [Citation(s) in RCA: 241] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/13/2012] [Accepted: 06/21/2012] [Indexed: 12/25/2022]
Abstract
Skeletal muscle plays an important role in regulating whole-body energy expenditure given it is a major site for glucose and lipid oxidation. Obesity and type 2 diabetes are causally linked through their association with skeletal muscle insulin resistance, while conversely exercise is known to improve whole body glucose homeostasis simultaneously with muscle insulin sensitivity. Exercise activates skeletal muscle AMP-activated protein kinase (AMPK). AMPK plays a role in regulating exercise capacity, skeletal muscle mitochondrial content and contraction-stimulated glucose uptake. Skeletal muscle AMPK is also thought to be important for regulating fatty acid metabolism; however, direct genetic evidence in this area is currently lacking. This review will discuss the current paradigms regarding the influence of AMPK in regulating skeletal muscle fatty acid metabolism and mitochondrial biogenesis at rest and during exercise, and highlight the potential implications in the development of insulin resistance.
Collapse
Affiliation(s)
- Hayley M O'Neill
- University of Melbourne, Department of Medicine, St. Vincent's Institute of Medical Research, Melbourne, Victoria, Australia.
| | | | | |
Collapse
|
33
|
Shiota A, Shimabukuro M, Fukuda D, Soeki T, Sato H, Uematsu E, Hirata Y, Kurobe H, Maeda N, Sakaue H, Masuzaki H, Shimomura I, Sata M. Telmisartan ameliorates insulin sensitivity by activating the AMPK/SIRT1 pathway in skeletal muscle of obese db/db mice. Cardiovasc Diabetol 2012; 11:139. [PMID: 23137106 PMCID: PMC3527353 DOI: 10.1186/1475-2840-11-139] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 10/18/2012] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Telmisartan is a well-established angiotensin II type 1 receptor blocker that improves insulin sensitivity in animal models of obesity and insulin resistance, as well as in humans. Telmisartan has been reported to function as a partial agonist of the peroxisome proliferator-activated receptor (PPAR) γ, which is also targeted by the nicotinamide adenine dinucleotide (NAD)-dependent deacetylase (SIRT1). Here, we investigated the pathways through which telmisartan acts on skeletal muscle, in vitro as well as in vivo. METHODS Nine-week-old male db/db mice were fed a 60% high-fat diet, with orally administrated either vehicle (carboxymethyl-cellulose, CMC), 5 mg/kg telmisartan, or 5 mg/kg telmisartan and 1 mg/kg GW9662, a selective irreversible antagonist of PPARγ, for 5 weeks. Effects of telmisartan on Sirt1 mRNA, AMPK phosphorylation, and NAD+/NADH ratio were determined in C2C12 cultured myocytes. RESULTS AND DISCUSSION Telmisartan treatment improved insulin sensitivity in obese db/db mice fed a high-fat diet and led to reduction in the size of hypertrophic pancreatic islets in these mice. Moreover, in vitro treatment with telmisartan led to increased expression of Sirt1 mRNA in C2C12 skeletal muscle cells; the increase in Sirt1 mRNA in telmisartan-treated C2C12 myoblasts occurred concomitantly with an increase in AMPK phosphorylation, an increase in NAD+/NADH ratio, and increases in the mRNA levels of PGC1α, FATP1, ACO, and GLUT4. CONCLUSIONS Our results indicate that telmisartan acts through a PPARγ-independent pathway, but at least partially exerts its effects by acting directly on skeletal muscle AMPK/SIRT1 pathways.
Collapse
Affiliation(s)
- Asuka Shiota
- Department of Cardio-Diabetes Medicine, University of Tokushima Graduate School of Health Biosciences, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Fernández-Galilea M, Pérez-Matute P, Prieto-Hontoria PL, Martinez JA, Moreno-Aliaga MJ. Effects of lipoic acid on lipolysis in 3T3-L1 adipocytes. J Lipid Res 2012; 53:2296-306. [PMID: 22941773 PMCID: PMC3465999 DOI: 10.1194/jlr.m027086] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 08/31/2012] [Indexed: 12/22/2022] Open
Abstract
Lipoic acid (LA) is a naturally occurring compound with beneficial effects on obesity. The aim of this study was to evaluate its effects on lipolysis in 3T3-L1 adipocytes and the mechanisms involved. Our results revealed that LA induced a dose- and time-dependent lipolytic action, which was reversed by pretreatment with the c-Jun N-terminal kinase inhibitor SP600125, the PKA inhibitor H89, and the AMP-activated protein kinase activator AICAR. In contrast, the PI3K/Akt inhibitor LY294002 and the PDE3B antagonist cilostamide enhanced LA-induced lipolysis. LA treatment for 1 h did not modify total protein content of hormone-sensitive lipase (HSL) but significantly increased the phosphorylation of HSL at Ser(563) and at Ser(660), which was reversed by H89. LA treatment also induced a marked increase in PKA-mediated perilipin phosphorylation. LA did not significantly modify the protein levels of adipose triglyceride lipase or its activator comparative gene identification 58 (CGI-58) and inhibitor G(0)/G(1) switch gene 2 (G0S2). Furthermore, LA caused a significant inhibition of adipose-specific phospholipase A2 (AdPLA) protein and mRNA levels in parallel with a decrease in the amount of prostaglandin E(2) released and an increase in cAMP content. Together, these data suggest that the lipolytic actions of LA are mainly mediated by phosphorylation of HSL through cAMP-mediated activation of protein kinase A probably through the inhibition of AdPLA and prostaglandin E(2).
Collapse
Affiliation(s)
- Marta Fernández-Galilea
- Department of Nutrition, Food Science, Physiology and Toxicology, University of Navarra, Pamplona, Spain; and
| | - Patricia Pérez-Matute
- Department of Nutrition, Food Science, Physiology and Toxicology, University of Navarra, Pamplona, Spain; and
- HIV and Associated Metabolic Alterations Unit, Infectious Diseases Area, Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Pedro L Prieto-Hontoria
- Department of Nutrition, Food Science, Physiology and Toxicology, University of Navarra, Pamplona, Spain; and
| | - J Alfredo Martinez
- Department of Nutrition, Food Science, Physiology and Toxicology, University of Navarra, Pamplona, Spain; and
| | - Maria J Moreno-Aliaga
- Department of Nutrition, Food Science, Physiology and Toxicology, University of Navarra, Pamplona, Spain; and
| |
Collapse
|
35
|
Hardie DG, Ross FA, Hawley SA. AMP-activated protein kinase: a target for drugs both ancient and modern. CHEMISTRY & BIOLOGY 2012; 19:1222-36. [PMID: 23102217 PMCID: PMC5722193 DOI: 10.1016/j.chembiol.2012.08.019] [Citation(s) in RCA: 281] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/28/2012] [Accepted: 08/31/2012] [Indexed: 02/07/2023]
Abstract
The AMP-activated protein kinase (AMPK) is a sensor of cellular energy status. It is activated, by a mechanism requiring the tumor suppressor LKB1, by metabolic stresses that increase cellular ADP:ATP and/or AMP:ATP ratios. Once activated, it switches on catabolic pathways that generate ATP, while switching off biosynthetic pathways and cell-cycle progress. These effects suggest that AMPK activators might be useful for treatment and/or prevention of type 2 diabetes and cancer. Indeed, AMPK is activated by the drugs metformin and salicylate, the latter being the major breakdown product of aspirin. Metformin is widely used to treat diabetes, while there is epidemiological evidence that both metformin and aspirin provide protection against cancer. We review the mechanisms of AMPK activation by these and other drugs, and by natural products derived from traditional herbal medicines.
Collapse
Affiliation(s)
- D Grahame Hardie
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK.
| | | | | |
Collapse
|
36
|
Lee JH, Moon MH, Jeong JK, Park YG, Lee YJ, Seol JW, Park SY. Sulforaphane induced adipolysis via hormone sensitive lipase activation, regulated by AMPK signaling pathway. Biochem Biophys Res Commun 2012; 426:492-7. [PMID: 22982310 DOI: 10.1016/j.bbrc.2012.08.107] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 08/22/2012] [Indexed: 10/27/2022]
Abstract
Sulforaphane, an aliphatic isothiocyanate derived from cruciferous vegetables, is known for its antidiabetic properties. The effects of sulforaphane on lipid metabolism in adipocytes are not clearly understood. Here, we investigated whether sulforaphane stimulates lipolysis. Mature adipocytes were incubated with sulforaphane for 24h and analyzed using a lipolysis assay which quantified glycerol released into the medium. We investigated gene expression of hormone-sensitive lipase (HSL), and levels of HSL phosphorylation and AMP-activated protein kinase on sulforaphane-mediated lipolysis in adipocytes. Sulforaphane promoted lipolysis and increased both HSL gene expression and HSL activation. Sulforaphane suppressed AMPK phosphorylation at Thr-172 in a dose-dependent manner, which was associated with a decrease in HSL phosphorylation at Ser-565, enhancing the phosphorylation of HSL Ser-563. Taken together, these results suggest that sulforaphane promotes lipolysis via hormone sensitive lipase activation mediated by decreasing AMPK signal activation in adipocytes.
Collapse
Affiliation(s)
- Ju-Hee Lee
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk 561 756, South Korea
| | | | | | | | | | | | | |
Collapse
|
37
|
Mason RR, Meex RCR, Lee-Young R, Canny BJ, Watt MJ. Phosphorylation of adipose triglyceride lipase Ser(404) is not related to 5'-AMPK activation during moderate-intensity exercise in humans. Am J Physiol Endocrinol Metab 2012; 303:E534-41. [PMID: 22713505 DOI: 10.1152/ajpendo.00082.2012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Intramyocellular triacylglycerol provides fatty acid substrate for ATP generation in contracting muscle. The protein adipose triglyceride lipase (ATGL) is a key regulator of triacylglycerol lipolysis and whole body energy metabolism at rest and during exercise, and ATGL activity is reported to be enhanced by 5'-AMP-activated protein kinase (AMPK)-mediated phosphorylation at Ser(406) in mice. This is a curious observation, because AMPK activation reduces lipolysis in several cell types. We investigated whether the phosphorylation of ATGL Ser(404) (corresponding to murine Ser(406)) was increased during exercise in human skeletal muscle and with pharmacological AMPK activation in myotubes in vitro. In human experiments, skeletal muscle and venous blood samples were obtained from recreationally active male subjects before and at 5 and 60 min during exercise. ATGL Ser(404) phosphorylation was not increased from rest during exercise, but ATGL Ser(404) phosphorylation correlated with myosin heavy chain 1 expression, suggesting a possible fiber type dependency. ATGL Ser(404) phosphorylation was not related to increases in AMPK activity, and immunoprecipitation experiments indicated no interaction between AMPK and ATGL. Rather, ATGL Ser(404) phosphorylation was associated with protein kinase A (PKA) signaling. ATGL Ser(406) phosphorylation in C(2)C(12) myotubes was unaffected by 5-aminoimidazole-4-carboxaminde-1-β-d-ribofuranoside, an AMPK activator, and the PKA activator forskolin. Our results demonstrate that ATGL Ser(404) phosphorylation is not increased in mixed skeletal muscle during moderate-intensity exercise and that AMPK does not appear to be an activating kinase for ATGL Ser(404/406) in skeletal muscle.
Collapse
Affiliation(s)
- Rachael R Mason
- Biology of Lipid Metabolism Laboratory, Department of Physiology, Monash University, Clayton, Victoria, Australia
| | | | | | | | | |
Collapse
|
38
|
Watt MJ, Hoy AJ. Lipid metabolism in skeletal muscle: generation of adaptive and maladaptive intracellular signals for cellular function. Am J Physiol Endocrinol Metab 2012; 302:E1315-28. [PMID: 22185843 DOI: 10.1152/ajpendo.00561.2011] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Fatty acids derived from adipose tissue lipolysis, intramyocellular triacylglycerol lipolysis, or de novo lipogenesis serve a variety of functions in skeletal muscle. The two major fates of fatty acids are mitochondrial oxidation to provide energy for the myocyte and storage within a variety of lipids, where they are stored primarily in discrete lipid droplets or serve as important structural components of membranes. In this review, we provide a brief overview of skeletal muscle fatty acid metabolism and highlight recent notable advances in the field. We then 1) discuss how lipids are stored in and mobilized from various subcellular locations to provide adaptive or maladaptive signals in the myocyte and 2) outline how lipid metabolites or metabolic byproducts derived from the actions of triacylglycerol metabolism or β-oxidation act as positive and negative regulators of insulin action. We have placed an emphasis on recent developments in the lipid biology field with respect to understanding skeletal muscle physiology and discuss unanswered questions and technical limitations for assessing lipid signaling in skeletal muscle.
Collapse
Affiliation(s)
- Matthew J Watt
- Biology of Lipid Metabolism Laboratory, Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
| | | |
Collapse
|
39
|
Granata R, Gallo D, Luque RM, Baragli A, Scarlatti F, Grande C, Gesmundo I, Córdoba-Chacón J, Bergandi L, Settanni F, Togliatto G, Volante M, Garetto S, Annunziata M, Chanclón B, Gargantini E, Rocchietto S, Matera L, Datta G, Morino M, Brizzi MF, Ong H, Camussi G, Castaño JP, Papotti M, Ghigo E. Obestatin regulates adipocyte function and protects against diet-induced insulin resistance and inflammation. FASEB J 2012; 26:3393-411. [PMID: 22601779 DOI: 10.1096/fj.11-201343] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The metabolic actions of the ghrelin gene-derived peptide obestatin are still unclear. We investigated obestatin effects in vitro, on adipocyte function, and in vivo, on insulin resistance and inflammation in mice fed a high-fat diet (HFD). Obestatin effects on apoptosis, differentiation, lipolysis, and glucose uptake were determined in vitro in mouse 3T3-L1 and in human subcutaneous (hSC) and omental (hOM) adipocytes. In vivo, the influence of obestatin on glucose metabolism was assessed in mice fed an HFD for 8 wk. 3T3-L1, hSC, and hOM preadipocytes and adipocytes secreted obestatin and showed specific binding for the hormone. Obestatin prevented apoptosis in 3T3-L1 preadipocytes by increasing phosphoinositide 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK)1/2 signaling. In both mice and human adipocytes, obestatin inhibited isoproterenol-induced lipolysis, promoted AMP-activated protein kinase phosphorylation, induced adiponectin, and reduced leptin secretion. Obestatin also enhanced glucose uptake in either the absence or presence of insulin, promoted GLUT4 translocation, and increased Akt phosphorylation and sirtuin 1 (SIRT1) protein expression. Inhibition of SIRT1 by small interfering RNA reduced obestatin-induced glucose uptake. In HFD-fed mice, obestatin reduced insulin resistance, increased insulin secretion from pancreatic islets, and reduced adipocyte apoptosis and inflammation in metabolic tissues. These results provide evidence of a novel role for obestatin in adipocyte function and glucose metabolism and suggest potential therapeutic perspectives in insulin resistance and metabolic dysfunctions.
Collapse
Affiliation(s)
- Riccarda Granata
- Laboratory of Molecular and Cellular Endocrinology, Department of Internal Medicine, University of Turin, Corso Dogliotti 14-10126 Turin, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Multidisciplinary pharmacotherapeutic options for nonalcoholic Fatty liver disease. Int J Hepatol 2012; 2012:950693. [PMID: 23304532 PMCID: PMC3523542 DOI: 10.1155/2012/950693] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 11/13/2012] [Indexed: 12/22/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are multidisciplinary liver diseases that often accompany type 2 diabetes or metabolic syndrome, which are characterized by insulin resistance. Therefore, effective treatment of type 2 diabetes and metabolic syndrome should target not only the cardiometabolic abnormalities, but also the associated liver disorders. In the last decade, it has been shown that metformin, thiazolidinediones, vitamin E, ezetimibe, n-3 polyunsaturated fatty acids, renin-angiotensin system (RAS) blockers, and antiobesity drugs may improve hepatic pathophysiological disorders as well as clinical parameters. Accordingly, insulin sensitizers, antioxidative agents, Niemann-Pick C1-like 1 (NPC1L1) inhibitors, RAS blockers, and drugs that target the central nervous system may represent candidate pharmacotherapies for NAFLD and possibly NASH. However, the efficacy, safety, and tolerability of long-term treatment (potentially for many years) with these drugs have not been fully established. Furthermore, clinical trials have not comprehensively examined the efficacy of lipid-lowering drugs (i.e., statins, fibrates, and NPC1L1 inhibitors) for the treatment of NAFLD. Although clinical evidence for RAS blockers and incretin-based agents (GLP-1 analogs and dipeptidyl peptidase-4 inhibitors) is also lacking, these agents are promising in terms of their insulin-sensitizing and anti-inflammatory effects without causing weight gain.
Collapse
|
41
|
Klaus S, Keipert S, Rossmeisl M, Kopecky J. Augmenting energy expenditure by mitochondrial uncoupling: a role of AMP-activated protein kinase. GENES AND NUTRITION 2011; 7:369-86. [PMID: 22139637 DOI: 10.1007/s12263-011-0260-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 11/18/2011] [Indexed: 11/28/2022]
Abstract
Strategies to prevent and treat obesity aim to decrease energy intake and/or increase energy expenditure. Regarding the increase of energy expenditure, two key intracellular targets may be considered (1) mitochondrial oxidative phosphorylation, the major site of ATP production, and (2) AMP-activated protein kinase (AMPK), the master regulator of cellular energy homeostasis. Experiments performed mainly in transgenic mice revealed a possibility to ameliorate obesity and associated disorders by mitochondrial uncoupling in metabolically relevant tissues, especially in white adipose tissue (WAT), skeletal muscle (SM), and liver. Thus, ectopic expression of brown fat-specific mitochondrial uncoupling protein 1 (UCP1) elicited major metabolic effects both at the cellular/tissue level and at the whole-body level. In addition to expected increases in energy expenditure, surprisingly complex phenotypic effects were detected. The consequences of mitochondrial uncoupling in WAT and SM are not identical, showing robust and stable obesity resistance accompanied by improvement of lipid metabolism in the case of ectopic UCP1 in WAT, while preservation of insulin sensitivity in the context of high-fat feeding represents the major outcome of muscle UCP1 expression. These complex responses could be largely explained by tissue-specific activation of AMPK, triggered by a depression of cellular energy charge. Experimental data support the idea that (1) while being always activated in response to mitochondrial uncoupling and compromised intracellular energy status in general, AMPK could augment energy expenditure and mediate local as well as whole-body effects; and (2) activation of AMPK alone does not lead to induction of energy expenditure and weight reduction.
Collapse
Affiliation(s)
- Susanne Klaus
- German Institute of Human Nutrition, Arthur-Scheunert-Allee 114-116, 14558, Nuthetal, Germany
| | | | | | | |
Collapse
|
42
|
Grisouard J, Timper K, Bouillet E, Radimerski T, Dembinski K, Frey DM, Peterli R, Zulewski H, Keller U, Müller B, Christ-Crain M. Metformin counters both lipolytic/inflammatory agents-decreased hormone sensitive lipase phosphorylation at Ser-554 and -induced lipolysis in human adipocytes. Arch Physiol Biochem 2011; 117:209-14. [PMID: 21338323 DOI: 10.3109/13813455.2010.550925] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVE To study the effects of metformin on lipolysis and hormone sensitive lipase (HSL) phosphorylation in human adipocytes treated with lipolytic and inflammatory agents. METHODS Lipolysis and phosphorylation status of HSL were assessed in subcutaneous pre-adipocytes surgically isolated from patients and differentiated into mature adipocytes in vitro. RESULTS Stimulation for 1 h with forskolin, isoproterenol and IBMX or stimulation for 24 h with LPS, IL-1β and TNF-α increased lipolysis (p < 0.05 vs. basal). The phosphorylation of HSL at Ser-554 was decreased while the Ser-552 phosphorylation was increased. Pre-incubation with metformin (24 h, 1 mM) inhibited forskolin-, isoproterenol-, IBMX-, LPS-, IL-1β- and TNF-α-induced glycerol release and prevented p(Ser554)HSL decrease and p(Ser-552)HSL increase due to lipolytic and inflammatory agents. AMPKα1 is involved in metformin-induced HSL phosphorylation at Ser-552. CONCLUSION Phosphorylation of HSL at Ser-554 inversely correlates with lipolysis and HSL phosphorylation at Ser552 in human adipocytes.
Collapse
Affiliation(s)
- Jean Grisouard
- University Hospital Basel, Department of Biomedicine, Switzerlands.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK. Biochem Biophys Res Commun 2011; 410:398-403. [DOI: 10.1016/j.bbrc.2011.05.143] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 05/28/2011] [Indexed: 11/24/2022]
|
44
|
Boyle JG, Logan PJ, Jones GC, Small M, Sattar N, Connell JMC, Cleland SJ, Salt IP. AMP-activated protein kinase is activated in adipose tissue of individuals with type 2 diabetes treated with metformin: a randomised glycaemia-controlled crossover study. Diabetologia 2011; 54:1799-809. [PMID: 21455728 DOI: 10.1007/s00125-011-2126-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 02/24/2011] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS The hypoglycaemic actions of metformin have been proposed to be mediated by hepatic AMP-activated protein kinase (AMPK). As the effects of metformin and the role of AMPK in adipose tissue remain poorly characterised, we examined the effect of metformin on AMPK activity in adipose tissue of individuals with type 2 diabetes in a randomised glycaemia-controlled crossover study. METHODS Twenty men with type 2 diabetes (aged 50-70 years) treated with diet, metformin or sulfonylurea alone were recruited from North Glasgow University National Health Service Trusts' diabetes clinics and randomised to either metformin or gliclazide for 10 weeks. Randomisation codes, generated by computer, were put into sealed envelopes and stored by the hospital pharmacist. Medication bottles were numbered, and allocation was done in sequence. The participants and investigators were blinded to group assignment. At the end of each phase of therapy adipose biopsy, AMPK activity (primary endpoint) and levels of lipid metabolism and signalling proteins were assessed. In parallel, the effect of metformin on AMPK and insulin-signalling pathways was investigated in 3T3-L1 adipocytes. RESULTS Ten participants were initially randomised to metformin and subsequently crossed over to gliclazide, while ten participants were initially randomised to gliclazide and subsequently crossed over to metformin. No participants discontinued the intervention and the adipose tissue AMPK activity was analysed in all 20 participants. There were no adverse events or side effects in the study group. Adipose AMPK activity was increased following metformin compared with gliclazide therapy (0.057 ± 0.007 vs 0.030 ± 0.005 [mean ± SEM] nmol min(-1) [mg lysate](-1); p < 0.005), independent of AMPK level, glycaemia or plasma adiponectin concentrations. The increase was associated with reduced levels of acetyl-CoA carboxylase (ACC) protein and increased ACC Ser80 phosphorylation. In 3T3-L1 adipocytes, metformin reduced levels of ACC protein and stimulated phosphorylation of AMPK Thr172 and hormone-sensitive lipase Ser565. CONCLUSIONS These results provide the first evidence that metformin activates AMPK and reduces ACC protein levels in human adipose tissue in vivo. Future studies are required to assess the role of adipose AMPK activation in the pharmacological effects of metformin. TRIAL REGISTRATION ISRCTN51336867.
Collapse
Affiliation(s)
- J G Boyle
- Institute of Cardiovascular and Medical Sciences, College of Medicine, Veterinary and Life Sciences, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Roland AV, Moenter SM. Prenatal androgenization of female mice programs an increase in firing activity of gonadotropin-releasing hormone (GnRH) neurons that is reversed by metformin treatment in adulthood. Endocrinology 2011; 152:618-28. [PMID: 21159854 PMCID: PMC3037157 DOI: 10.1210/en.2010-0823] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Prenatal androgenization (PNA) of female mice with dihydrotestosterone programs reproductive dysfunction in adulthood, characterized by elevated luteinizing hormone levels, irregular estrous cycles, and central abnormalities. Here, we evaluated activity of GnRH neurons from PNA mice and the effects of in vivo treatment with metformin, an activator of AMP-activated protein kinase (AMPK) that is commonly used to treat the fertility disorder polycystic ovary syndrome. Estrous cycles were monitored in PNA and control mice before and after metformin administration. Before metformin, cycles were longer in PNA mice and percent time in estrus lower; metformin normalized cycles in PNA mice. Extracellular recordings were used to monitor GnRH neuron firing activity in brain slices from diestrous mice. Firing rate was higher and quiescence lower in GnRH neurons from PNA mice, demonstrating increased GnRH neuron activity. Metformin treatment of PNA mice restored firing activity and LH to control levels. To assess whether AMPK activation contributed to the metformin-induced reduction in GnRH neuron activity, the AMPK antagonist compound C was acutely applied to cells. Compound C stimulated cells from metformin-treated, but not untreated, mice, suggesting that AMPK was activated in GnRH neurons, or afferent neurons, in the former group. GnRH neurons from metformin-treated mice also showed a reduced inhibitory response to low glucose. These studies indicate that PNA causes enhanced firing activity of GnRH neurons and elevated LH that are reversible by metformin, raising the possibility that central AMPK activation by metformin may play a role in its restoration of reproductive cycles in polycystic ovary syndrome.
Collapse
Affiliation(s)
- Alison V Roland
- Department of Medicine and Cell Biology, University of Virginia, Charlottesville, Virginia 22908, USA
| | | |
Collapse
|
46
|
Westerink J, Visseren FLJ. Pharmacological and non-pharmacological interventions to influence adipose tissue function. Cardiovasc Diabetol 2011; 10:13. [PMID: 21276223 PMCID: PMC3039566 DOI: 10.1186/1475-2840-10-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 01/28/2011] [Indexed: 12/31/2022] Open
Abstract
Obesity is associated with metabolic derangements such as insulin resistance, inflammation and hypercoagulobility which can all be understood as consequences of adipose tissue dysfunction. The potential role for adipose tissue derived cytokines and adipokines in the development of vascular disease and diabetes may produce a clinical need to influence adipose tissue function. Various pharmacological and non-pharmacological interventions affect plasma cytokine and adipokine levels. The effects of these interventions depend on weight loss per se, changes in fat distribution without weight loss and/or direct effects on adipose tissue inflammation. Weight loss, as a result of diet, pharmacology and surgery, positively influences plasma adipokines and systemic inflammation. Several classes of drugs influence systemic inflammation directly through their anti-inflammatory actions. PPAR-γ agonism positively influences adipose tissue inflammation in several classes of intervention such as the thiazolidinediones and perhaps salicylates, CB1-antagonists and angiotensin II receptor blockers. Furthermore, within drug classes there are differential effects of individual pharmacologic agents on adipose tissue function. It can be concluded that several commonly used pharmacological and non-pharmacological interventions have unintended influences on adipose tissue function. Improving adipose tissue function may contribute to reducing the risk of vascular diseases and the development of type 2 diabetes.
Collapse
Affiliation(s)
- Jan Westerink
- Department of Vascular Medicine, University Medical Center Utrecht, the Netherlands
| | | |
Collapse
|
47
|
Zhu M, Flynt L, Ghosh S, Mellema M, Banerjee A, Williams E, Panettieri RA, Shore SA. Anti-inflammatory effects of thiazolidinediones in human airway smooth muscle cells. Am J Respir Cell Mol Biol 2010; 45:111-9. [PMID: 20870897 DOI: 10.1165/rcmb.2009-0445oc] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Airway smooth muscle (ASM) cells have been reported to contribute to the inflammation of asthma. Because the thiazolidinediones (TZDs) exert anti-inflammatory effects, we examined the effects of troglitazone and rosiglitazone on the release of inflammatory moieties from cultured human ASM cells. Troglitazone dose-dependently reduced the IL-1β-induced release of IL-6 and vascular endothelial growth factor, the TNF-α-induced release of eotaxin and regulated on activation, normal T expressed and secreted (RANTES), and the IL-4-induced release of eotaxin. Rosiglitazone also inhibited the TNF-α-stimulated release of RANTES. Although TZDs are known to activate peroxisome proliferator-activated receptor-γ (PPARγ), these anti-inflammatory effects were not affected by a specific PPARγ inhibitor (GW 9662) or by the knockdown of PPARγ using short hairpin RNA. Troglitazone and rosiglitazone each caused the activation of adenosine monophosphate-activated protein kinase (AMPK), as detected by Western blotting using a phospho-AMPK antibody. The anti-inflammatory effects of TZDs were largely mimicked by the AMPK activators, 5-amino-4-imidazolecarboxamide ribose (AICAR) and metformin. However, the AMPK inhibitors, Ara A and Compound C, were not effective in preventing the anti-inflammatory effects of troglitazone or rosiglitzone, suggesting that the effects of these TZDs are likely not mediated through the activation of AMPK. These data indicate that TZDs inhibit the release of a variety of inflammatory mediators from human ASM cells, suggesting that they may be useful in the treatment of asthma, and the data also indicate that the effects of TZDs are not mediated by PPARγ or AMPK.
Collapse
Affiliation(s)
- Ming Zhu
- Molecular and Integrative Physiological Sciences Program, Department of Environmental Health, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115-6021, USA
| | | | | | | | | | | | | | | |
Collapse
|